Diagnosis of different kinds of acute leukemia depends commonly upon the appearance of nuclear chromatin, nucleoli nucleocytoplasmic ratio and cytoplasmic features in blastc cells on Romanowsky staining. Twenty-five patients with acute leukemia in either initial presentation, relapse or remission were studied by submitting material to 5 different types of commonly used Romanowsky stains. The results that the commonly used criteria in the diagnosis of acute leukemia depend on the kind of Romanowsky stain used. Differential characteristics used to separate acute lymphocytic leukemia (ALL) from acute myeloblastic leukemia (AML), for instance, changes with the kind of stain used. This affects the statistical composition of a leukemia population within a given diagnostic area.